Voltammetric ion-selective biosensor

Abstract

A method for the quantitative determination of an ion in a fluid is described which comprises subjecting the fluid to voltammetry using an electrode which comprises an electrically conducting support possessing a coating of a solid capable of selecting ions when electrochemically induced during operation.

1 . A method for the quantitative determination of an ion in a fluid which comprises subjecting the fluid to voltammetry using an electrode which comprises an electrically conducting support possessing a coating of a solid capable of selecting ions when electrochemically induced during operation.  
     
     
         2 . A method according to  claim 1  wherein the solid is a redox active material.  
     
     
         3 . A method according to  claim 1  wherein the solid undergoes a reversible ingress/egress of ions when electrochemically induced.  
     
     
         4 . A method according to  claim 3  wherein the solid undergoes a selective reversible ingress/egress of ions when electrochemically induced.  
     
     
         5 . A method according to  claim 4  wherein the solid is a synmetal.  
     
     
         6 . A method according to  claim 1  wherein the solid is either the donor or acceptor of a charge transfer salt pair.  
     
     
         7 . A method according to  claim 6  wherein the solid is tetracyanoquinodimethane or tetrathiafulvalene or an analogue or derivative thereof.  
     
     
         8 . A method according to  claim 1  wherein the support is formed of a metal or carbon.  
     
     
         9 . A method according to  claim 1  wherein the solid coating has an ion exchange membrane over it, the membrane being capable of exchanging ions of the same charge as those capable of being intercalated by the solid.  
     
     
         10 . A method according to  claim 1  wherein the fluid contains more than one anion or cation and the solid is one which provides the more or most positive mid point potential for the cation to be determined in a mixture of cations or the more or most negative mid point potential for the anion to be determined in a mixture of anions.  
     
     
         11 . A method according to  claim 1  wherein the fluid is placed in a cell comprising the electrode, a counter electrode for supplying a potential differences, and a reference electrode.  
     
     
         12 . A method according to  claim 11  wherein the cell forms a microelectrode.  
     
     
         13 . A method according to  claim 1  wherein the electrode is reset following a determination by voltammetric cycling.  
     
     
         14 . (Cancelled)  
     
     
         15 . A device for the quantitative determination of an ion in a fluid by subjecting the fluid to voltammetry, the device comprising an electrode having an electrically conducting support that possesses a coating of a solid capable of selecting ions when electrochemically induced during operation of the device.  
     
     
         16 . A device for the quantitative determination of an ion in a fluid which device comprises a receptacle for said fluid, the receptacle comprising an electrode that possesses a coating of a solid capable of selecting ions when electrochemically induced during operation of the device, and a counter electrode for supplying a potential difference.  
     
     
         17 . A device according to  claim 31  wherein the electrode, the counter electrode and the reference electrode comprise three conductive tracks on a single support.  
     
     
         18 . A device according to  claim 16  wherein the counter electrode comprises an electrically conducting support possessing a coating of a solid capable of selecting ions when electrochemically induced during operation.  
     
     
         19 . A support comprising at least two conductive tracks, one track forming an electrode having a coating of a solid capable of selecting ions when electrochemically induced during operation and another track forming a counter electrode for supplying a potential difference, and the support further comprising a reference electrode.  
     
     
         20 . A support according to  claim 19  comprising a reference electrode as a third track.  
     
     
         21 . An electrode which comprises an electrically conducting support possessing a coating of a solid capable of intercalation of ions when electrochemically induced during operation, said solid not being tetracyanoquinodimethane or tetrathiafulvalene.  
     
     
         22 . (Canceled)  
     
     
         23 . A method according to  claim 15  wherein the solid is a redox active material.  
     
     
         24 . A device according to  claim 15  wherein the solid undergoes a reversible ingress/egress of ions when electrochemically induced.  
     
     
         25 . A device according to  claim 15  wherein the solid undergoes a selective reversible ingress/egress of ions when electrochemically induced.  
     
     
         26 . A device according to  claim 15  wherein the solid is a synmetal.  
     
     
         27 . A device according to  claim 15  wherein the solid is either the donor or acceptor of a charge transfer salt pair.  
     
     
         28 . A device according to  claim 27  wherein the solid is tetracyanoquinodimethane or tetrathiafulvalene or an analogue or derivative thereof.  
     
     
         29 . A device according to  claim 15  wherein the support is formed of a metal or carbon.  
     
     
         30 . A device according to  claim 15  wherein the coating has an ion exchange membrane over it, the membrane being capable of exchanging ions of the same charge as those capable of being intercalated by the solid.  
     
     
         31 . A device according to  claim 16  further comprising a reference electrode.